Cryogenic filling valve

ABSTRACT

The invention relates to a valve suitable for use as a cryogenic filling valve for high-pressure gas cylinders, which valve comprises a body adapted to be connected in a gastight manner to an inlet of a gas cylinder; a first passageway extending through the body and adapted to receive a probe so as to permit liquid to pass from the probe into the cylinder to which the body is connected; first valve means for opening and closing said first passageway; a second passageway extending through the body for permitting gas to be drawn off from the cylinder; and second valve means for controlling the rate at which gas passes through the second passageway. The valve enables liquefied gas to be charged to the gas cylinder and also serves to control the delivery from the cylinder of gas produced by evaporation of the liquefied gas so charged. In a preferred embodiment, an inner vessel is provided in the gas cylinder to receive the liquefied gas charged thereto and to allow evaporated gas to pass into the remainder of the cylinder.

United States Patent Finney 1 Feb. 29, 1972 [541 CRYOGENIC FILLING VALVE [72] Inventor: Peter E. Finney, Knotty Green, Beacon- [30] Foreign Application Priority Data May 6, 1968 Great Britain .....2l,399/68 May 6, 1968 Great Britain... ..21,400/68 3,307,597 3/1967 Shugarman ..141/18 713,975 11/1902 FOrg ...l37/588 1,641,328 9/1927 Ferdinand ..141/18 2,529,275 11/1950 Blumer et al. ..137/588 Primary ExaminerRaphael H. Schwartz Attorney-Stevens, Davis, Miller & Mosher [5 7] ABSTRACT The invention relates to a valve suitable for use as a cryogenic filling valve for high-pressure gas cylinders, which valve comprises a body adapted to be connected in a gastight manner to an inlet of a gas cylinder; a first passageway extending through the body and adapted to receive a probe so as to permit liquid to pass from the probe into the cylinder to which the body is connected; first valve means for opening and closing said first passageway; a second passageway extending through the body for permitting gas to be drawn 01? from the cylinder; and second valve means for controlling the rate at which gas passes through the second passageway. The valve enables 56] References Cited liquefied gas to be charged to the gas cylinder and also serves to control the delivery from the cylinder of gas produced by UNITED STATES PATENTS evaporation of the liquefied gas so charged. In a preferred embodiment, an inner vessel is provided in the gas cylinder to 3,2621 82 l 1/1941 Huskamp ..2l7/100 receive the liquefied gas charged thereto and to allow 2/195 1 Clam" evaporated gas to pass into the remainder of the cylinder. 2,656,067 10/1953 Mitchell... ..220/86 2,794,452 6/1957 Quam ..222/402.16 X 5 Claims, 6 Drawing Figures PAIENTEDFEB 29 1972 SHEET 2 0? 2 /N VE/VTOR I PE R E PHI/95y 5 CHM/I1 r;

' AT TOR/V5 Y5 CRYOGENIC FILLING VALVE The present invention relates to a valve suitable for use as a cryogenic filling valve for high-pressure gas cylinders and to a method of filling gas cylinders employing said valve.

The methods usually employed for filling cylinders with gas under a pressure in excess of atmospheric pressure comprise pumping gas through filling valves of conventional type into said cylinders until the desired pressure is reached. Such methods, however, often require the generation of considerable gas pressures, which generation is costly in terms of both energy and apparatus requirements. When filling gas containers with gases which are produced and/or stored in bulk in the liquefied state, the above-mentioned methods require additional energy to evaporate the gas prior to compression. A simpler method of filling gas cylinders with a gas which is produced and/or stored in bulk in the liquefied state would be to charge the gas cylinder with a predetermined quantity of said liquefied gas, to make the cylinder gastight and to allow or cause the liquefied gas to evaporate in the gas container thereby generating gas at the desired pressure.

According to the present invention, there is provided a valve suitable for use as a cryogenic filling valve for high-pressure gas cylinders comprising a body adapted to be connected in a gastight manner to an inlet of a gas cylinder; a first passageway extending through the body and adapted to receive a probe so as to permit liquid to pass from the probe into the cylinder to which the body is connected; first valve means for opening and closing said first passageway; a second passageway extending through the body for permitting gas to be drawn off from the cylinder; and second valve means for controlling the rate at which gas passes through the second passageway.

The invention also provides a process of filling a gas cylinder having a valve of the invention connected to an inlet of the cylinder in a gastight manner, which process comprises the steps of inserting the tip of a probe into the first passageway; moving the first valve means to open the first passageway before, during or after said insertion of the probe; supplying a predetermined quantity of liquefied gas to the cylinder via the probe; withdrawing the probe from the first passageway; moving the first valve means to close the first passageway before, during or after said withdrawal; and causing or allowing the liquefied gas to evaporate to produce in the cylinder a gas at the desired pressure. The gas so generated may be drawn off as and when desired through the second passageway of the valve according to the invention, the rate of flow of gas therethrough being controlled by the second valve means.

The first passageway may be a straight bore which extends through the body of the valve to connect the interior of the cylinder to which the valve is connected with the surrounding atmosphere. The length and disposition of this bore is conveniently such that the tip of a probe employed to supply liquefied gas to the cylinder passes through the passageway into the gas cylinder.

The first valve means may be any means capable of opening the first passageway to permit a probe to discharge liquid into the cylinder and of subsequently closing the passageway to prevent the escape of gas therethrough. A simple form of such valve means is a plug adapted to be a gastight fit in the mouth of the first passageway at the atmospheric end thereof and to be removed from said mouth to allow a probe to pass therethrough. The speed at which the first passageway need be closed after charging the cylinder with liquefied gas is dependent upon the rate of evaporation of the liquefied gas charged to the cylinder. This rate of evaporation is often fairly slow and hence rapid closure of the passageway although preferred is not essential. Thus a manually operated closure plug as mentioned above may be employed without substantial gas losses and the losses which do occur can be allowed for by adjusting the quantity of liquefied gas charged to the cylinder and by replacing the plug a predetermined time after charging the liquefied gas to the cylinder. 1

The simple plug closure does however have a number of disadvantages as does any manually operated closing device and it is a preferred feature of this invention that the first valve means is operable by movement of the probe. With such a probe-operated valve means, the filling process may be reduced to simply inserting the tip of the probe into the first passageway, which movement of the probe opens the first valve means, and then allowing a predetermined quantity of liquid to flow through the probe into the cylinder. Subsequent removal of the probe from the first passageway causes or allows the probe-operated first valve means to close said passageway.

A relatively simple and yet effective probe-operated first valve means has been found to be a pivotally mounted closure member adapted to seat against the cylinder end of the first passageway, the arrangement being such that abutment of the closure member with the tip of a probe inserted into the first passageway causes said member to pivot about its mounting thereby permitting the probe tip to enter the cylinder and such that withdrawal of the probe tip from the cylinder after the cylinder has been charged with liquefied gas allows the closure member to return to seat against the end of the passageway. The return of the closure member may be effected by the gas pressure buildup in the cylinder alone although it is preferred that the closure member should be lightly biassed by, for example, spring loading into its closed position. One advantage of a valve means constituted by such a closure member is that the greater the gas pressure in the gas cylinder the greater the force with which the closure member seats against the cylinder end of the first passageway and accordingly the greater the degree of sealing of the first passageway.

The second passageway may be constituted by a straight bore extending through the body of the valve to connect the interior of the cylinder with the surrounding atmosphere. Alternatively, the second passageway may be constituted by a bore extending between the cylinder end of the valve and the first passageway at a point beyond, with respect to the cylinder end of the valve, the first valve means.

The second valve means may be any means capable of regulating the flow of gas through the second passageway and of closing said passageway in a gastight manner. Such a valve means may be provided externally of the said passageway, for example by a conventional high-pressure valve adapted to cooperate with the second passageway at the atmospheric end thereof, or may be provided within the second passageway itself. If desired the second valve means may incorporate a pressure regulator.

Although the valve of the present invention may be employed with any gas cylinder having a neck of sufficient diameter to receive the valve, it is preferred that an inner vessel is provided within the gas cylinder to receive liquefied gas charged thereto via the valve and thereby substantially to isolate the liquefied gas from the walls of the cylinder thus ensuring slower and more even evaporation of the liquefied gas. The inner vessel is provided with gas outlet means to allow gas to pass into the remainder of the cylinder cavity on evaporation of the liquefied gas.

As specified above, the inner vessel is substantially isolated from the walls of the gas cylinder and thus if the inner vessel and the gas cylinder do share a common wall portion or have wall portions in contact, said portion of the inner vessel will constitute a minor part only of the inner vessel. Since the inner vessel is intended to receive liquefied gas, it is constructed of a cryogenically acceptable material, e.g., mylar foil. The walls of the gas cylinder will not under normal circumstances be contacted with the liquefied gas and hence the cryogenic requirements for the material thereof are somewhat less than the requirements for the inner vessel.

If desired the inner vessel can be collapsible for insertion through the inlet into the cylinder and adapted to be attached to the inlet for retention in the cylinder.

In a preferred gas cylinder which I have devised for use in combination with a valve of the present invention, a cylindrical gas cylinder having a combined inlet and outlet extending through a neck is provided with an inner vessel constituted by a downward extension of said neck and an otherwise closed liquefied gas-receiving vessel into which the extension opens, said extension being provided with at least one radially extending hole through which gas can flow into and out of the remainder of the cylinder cavity. In this arrangement, liquefied gas charged to the cylinder via a valve of the invention disposed in the cylinder neck passes directly into the liquefied gas-receiving vessel and gas generated by evaporation in that vessel passes through the at least one hole in the extension into the remainder of the cylinder cavity until uniform gas pressure is attained throughout the cavity, both inside and outside the liquefied gas-receiving vessel. If liquefied gas is supplied to the cylinder in sufficient quantity to reach a level in the inner vessel above said at least one hole, gas generated by evaporation of the liquefied gas will be unable to escape into the remainder of the cylinder cavity and will cause a blowback of liquefied gas. Thus, if the said hole or holes are so disposed in the extension that when liquefied gas is supplied to the cylinder it will reach the level of said hole or holes when the inner vessel contains the desired predetermined quantity of liquefied gas, the blowback caused by an increase in liquid level above said hole(s) serves as an indication that the predetermined quantity of liquefied gas has been charged to the gas cylinder.

When the valve of the present invention is employed as a cryogenic filling valve, its primary function will be for use in adapting gas cylinders so that they can be charged with liquefied nitrogen, liquefied oxygen or liquefied argon and hence both the valve and the cylinder should be constructed of suitable cryogenically acceptable material, for example aluminum, brass, copper or stainless steel. When filling cylinders with gas for ordinary commercial purposes, the quantity of liquefied gas fed to the container will usually be sufficient to generate a gas of 1,800 lbs. per sq. inch, the quantity of liquefied gasadded being 2 liters per 50 cu. ft. at N.T.P.

The following is a description by way of example only and with reference to the accompanying drawings of a cryogenic filling valve in accordance with the present invention and of a gas cylinder suitable for use in combination with the valve.

In the drawings:

FIG. I is a top view of a valve in accordance with the present invention;

FIG. 2 is a sectional view of the valve of FIG. 1 along the line A-A;

FIG. 3 is a sectional view of the valve of FIG. 1 along the line B-B;

FIG. 4 is a sectional view of the valve of FIG. 1 along the line C-C;

FIG. 5 is a bottom view of the valve of FIG. 1; and

FIG. 6 is a sectional view through a longitudinal axis of a gas cylinder suitable for use in combination with the valve shown in FIGS. 1-6.

A cryogenic filling valve generally indicated at 1 comprises a body 2 formed of a cylindrical lower portion 3 extending coaxially from a cylindrical upper portion 4. The lower portion is externally threaded to be received in an internally threaded neck of a wide neck gas cylinder and the shoulder formed at the junction of said portions 3, 4 is provided with an annular groove 5 to receive an O-ring seal 6. This O-ring seal ensures a gastight fit between said shoulder and the rim of the gas cylinder neck. The body also is formed with an annular groove 5 extending circumferentially about portion 3 immediately below the lowest thread.

A first passageway or filling part is constituted by a bore 7 of uniform diameter which extends through the body 2 at a slight angle to the axial direction. A second bore 8 also extends through the body 2 in an axial direction and is constituted by four bore portions 9, 10, 11, 12 of different diameters, although each bore portion is of uniform diameter along its length. The first or upper bore portion 9 extends from the upper face of the body 2 and the bore 8 is continued downwardly from that portion in the second bore portion 10. This bore portion 10 is of reduced diameter compared with the first bore portion 9 and is threaded to receive an externally threaded portion of the body 26 of a needle valve 27. The third bore portion 11 is of smaller diameter than the first and second bore portions and terminates within the upper body portion 4. The bore 8 is completed by the fourth or lower bore portion 12 which is of considerably smaller diameter than the other bore portions and extends between bore portion 11 and the lower face of the body 2.

A third bore 13 extends into the body 2 from the upper face thereof and is formed of an upper bore portion 14 and a lower bore portion 15 joined by an upwardly divergent bore portion 16. Upper bore portion 14 is of uniform diameter and is threaded to receive a bullnosed adapter (not shown), which adapter is itself adapted to receive a high-pressure valve of conventional type thereby connecting said high-pressure valve to the third bore 13. The lower bore portion 15 also is of uniform diameter but is considerably narrower than the upper bore portion 14. This bore portion 15 extends into the lower body portion 3 and communicates at its lower end with an inclined uniform bore 17 depending from the third bore portion 11. The extent to which bore 13 extends into the body portion 3 and the inclination of bore 17 are determined by manufacturing techniques in that only limited access is available via bore 8 to drill bore 17.

The filling part 7 normally is closed at its lower end by a closure member 18 which is formed of a disclike lower portion having the center of the upper face thereof extended axially in a dome 19. An annular groove 20 extends into said upper face about the dome l9 and is formed with upwardly convergent sidewalls to provide positive location for an O-ring seal 21. A circumferentially extending annular groove 22 is formed about the closure member and accommodates a wire loop of a light wire spring 23. This spring 23 is attached to the body 2 by a spaced pair of screws 24 threadably received in cooperating threaded bores extending into the lower face of body portion 3, the arrangement being such that said spring 23 not only biases the closure member 18 into a position where the O-ring seal 21 seats against the lower face of the body portion 3 and thereby closes the filling port 7 but also provides a pivotal mounting between screws 24 about which the closure member can move. Abutment of a probe tip passed through the filling port 7 from the upper end thereof with the dome 19 will cause the closure member 18 to pivot downwardly against its spring bias to open said port 7 and to allow the probe tip to extend from the valve body 2.

The bore portion 11 accommodates an annular insert 25 maintained with its central bore coaxial with lower bore portion 12 by location in the lower end of the needle valve body 26. The insert 25 serves as a seat for the spindle 28 of the needle valve 27 and accommodates in an annular groove in its lower surface an O-ring seal 29. The valve body 26 has an enlarged intermediate portion which is externally threaded to cooperate with threaded bore portion 10 and below that intermediate portion is a sliding fit in the bore portion 1 1. This fit is rendered gastight by an O-ring seal 30 disposed in a circumferentially extending groove in the body 26. A bore 31 extends axially through the body 26 and has an intermediate portion 32 of reduced diameter. This portion 32 is threaded at its lower end to receive from that end an externally threaded portion 35 of the spindle 28. The bore 31 is restricted further towards the top of the intennediate portion 32 by a radially inwardly extending flange 33 adapted to be a sliding fit about the main shaft 28' of the spindle 28. The upper portion of the bore 31 is threaded to receive a gland nut 34.

A groove 36 extends circumferentially about the body 26 at the level of the mouth to the inclined bore 17 and communicates with the lower part of bore 31 by means of four holes radially extending through the body 26. This arrangement permits gas entering the bore 31 via bore portion 12 to pass into inclined bore 17 and thence via bore 13 from the valve 1.

The spindle 28 is accommodated in the bore 31 by threadable engagement with the walls of the intermediate bore portion 32 and the sliding fit of shaft 28 in the flange 33. The spindle can be caused to move axially in bore 31 into and out of engagement with the insert 25 so as to control the flow of gas through the bore portion 12 by rotation thereof with respect to bore portion 32. To facilitate rotation of the spindle, the upper end thereof is square in cross section. The needle valve assembly is rendered gastight by location of a hexagonally headed gland nut 34 about the portion of spindle 27 accommodated in the upper portion of bore 31 and by clamping of an O-ring seal 35 between the lower surface of said gland nut 34 and the upper surface of the flange 33.

In operation with the lower portion 3 of the valve I screwed into the neck of a wide neck gas cylinder, a probe, which is connected to a source of liquefied gas and has a bore extending therethrough to terminate in an outlet for liquefied gas at the probe tip, is inserted into the filling port 7 from the upper end thereof. The tip of the probe is moved downwardly through. said port to abut the dome 19 of closure member 18 thereby causing the closure member to pivot against its spring bias to open the filling port and allow the probe tip to enter the body of the gas cylinder. Liquefied gas is then passed through the probe into the cylinder and the probe is withdrawn after a predetermined quantity of liquefied gas has been so charged to the cylinder. Withdrawal of the probe allows the closure member to return under its spring bias to seat the O-ring seal 21 against the body 2 thus closing the filling port. Evaporation of the liquefied gas in the cylinder generates gas of the desired pressure, which pressure acts upon the closure member 18 to urge this member more firmly against the body 2.

When it is desired to discharge gas from the cylinder, a bullnosed adapter carrying a conventional high-pressure valve is screwed into the threaded upper portion 14 of the bore 13. The needle valve spindle 28 is then rotated so as to withdraw the lower end thereof from the insert 25 thereby permitting gas to flow from the cylinder through the. bore portion 12 into the bore 31. Gas entering this bore 31 will flow through the holes 37 into groove 36 and thence via inclined bore 17 and bore 13 to the bullnosed adapter and the high-pressure valve. After the desired quantity of gas has been discharged, the spindle 28 is rotated to seat the lower end thereof in the insert 25 thus preventing flow of gas into the bore 31.

The rate at which gas is supplied for the cylinder can then be controlled in conventional manner by the high-pressure valve.

Although the operation of the cryogenic valve has been described with reference to filling and discharging of a single gas cylinder, the valve may be employed for cascade filling of gas cylinders. In the cascade process, a first cylinder is charged with liquefied gas and is then connected to at least one further gas cylinder to allow gas generated in the first cylinder to flow into said at least one further cylinder(s) thereby filling the same with gas.

A gas cylinder which is particularly useful in combination with the valve described above is generally indicated at 40 and comprises a conventional high-pressure gas cylinder 41 of the wide neck type being formed of a hollow substantially cylindrical body of aluminum closed at its lower end and tapering at its upper end to form a neck 42, which neck is internally threaded at its narrower lower end 42. An inner vessel 43 is accommodated within the cylinder 41 and depends axially into the cylinder from the base of the neck 42 when a valve 1 is threadably received therein. (Valve 1 has been omitted from FIG. 6 for clarity). This inner vessel 43 is formed of an aluminum tube 44 having an upper cylindrical portion 45, which is swaged at its upper end into the groove 5 in valve 1, and a narrower lower cylindrical portion 46, which is closed at its lower end. A sleeve of mylar foil is attached to the lower portion 46 both towards its upper end and towards its lower end so as to form a closed mylar bag 47. The attachment of the sleeve 47 to the lower portion 46 suitably may be effected by gluing the sleeve to the lower portion and then tying string about the glued portion of the sleeve. A hole 48 of rectangular cross section extends radially through the wall of upper portion 45 to allow gas to flow into and out of the gas cylinder cavity surrounding the inner vessel. This hole 48 is large enough and is so disposed that, in operation, the closure member 18 can open into the hole thus permitting the lower end of part 7 to be fully opened. The lower portion 46 is per' forated with a plurality of small diameter holes 49 to permit liquefied gas to flow into the mylar bag and subsequently to allow gas generated in that bag to flow into tube 44 and thence into the remainder of the gas cylinder cavity.

The inner vessel 43 is suspended within the cylinder 41 by attaching the upper end of portion 45 to the neck 42. Thus, in its extended state the inner vessel constitutes an axial extension of the neck of the conventional cylinder and the mylar bag is disposed with its walls spaced from the walls of the cylinder 41. When the inner vessel is first placed in the cylinder 41 the mylar bag will lie in a collapsed state in order to allow it to pass through the neck 42 and hence it will be necessary to inflate said bag. This conveniently may be done by simply blowing gas down the neck 42.

In operation, the cryogenic filling valve described above is screwed into the neck 42 of the cylinder 40. Liquefied gas is then charged through said valve into the cylinder, which liquefied gas flows via the tube 44 into the mylar bag 47 and accumulates therein. When a predetermined quantity of liquefied gas has been charged to the cylinder, the valve 1 is closed rendering the cylinder gastight. If desired, the inner vessel may have a sufficient capacity up to the level of the hole 48 to constitute the predetermined quantity of liquefied gas the mylar bag 47 and the gas so generated will pass from the bag 47 through the holes 49 into tube 44 andthen through hole 48 into the cavity of the cylinder 41. Such evaporation will continue until all of the liquefied gas has evaporated and the flow of gas from the inner vessel 43 will continue until the gas pressure around the inner vessel is equal to the gas pressure within the inner vessel. The gas so generated in the gas cylinder may be discharged when desired through the valve, on which discharge gas flows via holes 4? from within the inner vessel and from about the inner vessel via hole 48 into the bore 8.

The cylinder 40 described above provided a slower and more even evaporation of liquefied gas than that evaporation which occurred when the conventional cylinder 41 alone was charged with liquefied gas.

I claim:

1. A cryogenic filling valve for high-pressure gas cylinders, comprising: a valve body having an upper face and a cylinder face; a first passageway having a straight bore extending through said valve body; first valve means opening and closing said first passageway; a second passageway extending through said valve body, said second passageway comprising first and second portions, said first portion having a larger diameter than said second portion, said second portion extending into said valve body from said cylinder face, said first portion extending from said second portion to said upper face of said valve body; a valve member entirely received within said first portion, including an adjustable needle valve, mounted in said first portion, said needle valve being seated in said second portion where said second portion enters said first portion, said needle valve being operable to adjust the opening of said second portion into said first portion; and a third passageway extending into said valve body from said upper face, said third passageway being in communication with said first portion, wherein when said needle valve is in an open position, a passageway extends from the upper face of said valve body to the cylinder face thereof through said third passageway, said first portion and said second portion.

2. A cryogenic filling valve according to claim 1, wherein said third passageway comprises: one portion extending into said valve body from said upper face substantially parallel with said second passageway and another portion extending diagonally from a portion of said first portion in communication with said second portion to said one portion of said third passageway.

3. A valve as claimed in claim 1 wherein the first valve means is adapted to be operated by movement of a probe in- 

1. A cryogenic filling valve for high-pressure gas cylinders, comprising: a valve body having an upper face and a cylinder face; a first passageway having a straight bore extending through said valve body; first valve means opening and closing said first passageway; a second passageway extending through said valve body, said second passageway comprising first and second portions, said first portion having a larger diameter than said second portion, said second portion extending into said valve body from said cylinder face, said first portion extending from said second portion to said upper face of said valve body; a valve member entirely received within said first portion, including an adjustable needle valve, mounted in said first portion, said needle valve being seated in said second portion where said second portion enters said first portion, said needle valve being operable to adjust the opening of said second portion into said first portion; and a third passageway extending into said valve body from said upper face, said third passageway being in communication with said first portion, wherein when said needle valve is in an open position, a passageway extends from the upper face of said valve body to the cylinder face thereof through said third passageway, said first portion and said second portion.
 2. A cryogenic filling valve according to claim 1, wherein said third passageway comprises: one portion extending into said valve body from said upper face substantially parallel with said second passageway and another portion extending diagonally from a portion of said first portion in communication with said second portion to said one portion of said third passageway.
 3. A valve as claimed in claim 1 wherein the first valve means is adapted to be operated by movement of a probe inserted in the first passageway.
 4. A valve as claimed in claim 3 wherein the first valve means comprises a pivotally mounted closure member adapted to seat against the cylinder end of the firsT passageway.
 5. A valve as claimed in claim 4 wherein the closure member is biassed into its closed position. 